title: Depletion of PINK1 affects mitochondrial metabolism, calcium homeostasis and energy maintenance.
abstract: Loss-of-function mutations in the gene encoding the mitochondrial PTEN-induced putative kinase 1 (PINK1) are a major cause of early-onset familial Parkinson's disease (PD). Recent studies have highlighted an important function for PINK1 in clearing depolarized mitochondria by mitophagy. However, the role of PINK1 in mitochondrial and cellular functioning in physiological conditions is still incompletely understood. Here, we investigate mitochondrial and cellular calcium (Ca(2+)) homeostasis in PINK1-knockdown and PINK1-knockout mouse cells, both in basal metabolic conditions and after physiological stimulation, using unbiased automated live single-cell imaging in combination with organelle-specific fluorescent probes. Our data reveal that depletion of PINK1 induces moderate fragmentation of the mitochondrial network, mitochondrial membrane depolarization and increased production of reactive oxygen species. This results in reduced uptake of Ca(2+) by mitochondria after physiological stimulation. As a consequence, cells with knockdown or knockout of PINK1 display impaired mitochondrial ATP synthesis, which is exacerbated under conditions of increased ATP demand, thereby affecting cytosolic Ca(2+) extrusion. The impairment in energy maintenance was confirmed in the brain of PINK1-knockout mice by in vivo bioluminescence imaging. Our findings demonstrate a key role for PINK1 in the regulation of mitochondrial homeostasis and energy metabolism under physiological conditions.
authors.affiliation: Laboratory for Neurobiology and Gene Therapy, Molecular Medicine, Katholieke Universiteit Leuven, 3000 Leuven, Flanders, Belgium.
authors.forename: Bavo
authors.initials: B
authors.lastname: Heeman
authors.forename: Chris
authors.initials: C
authors.lastname: Van den Haute
authors.forename: Sarah-Ann
authors.initials: SA
authors.lastname: Aelvoet
authors.forename: Federica
authors.initials: F
authors.lastname: Valsecchi
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Rodenburg
authors.forename: Veerle
authors.initials: V
authors.lastname: Reumers
authors.forename: Zeger
authors.initials: Z
authors.lastname: Debyser
authors.forename: Geert
authors.initials: G
authors.lastname: Callewaert
authors.forename: Werner J H
authors.initials: WJ
authors.lastname: Koopman
authors.forename: Peter H G M
authors.initials: PH
authors.lastname: Willems
authors.forename: Veerle
authors.initials: V
authors.lastname: Baekelandt
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004195:Disease Models, Animal; D004734:Energy Metabolism; D005260:Female; D055785:Gene Knockdown Techniques; D006706:Homeostasis; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008928:Mitochondria / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D010300:Parkinson Disease / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D011494:Protein Kinases / Q000172:deficiency* / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D000099202:PTEN-Induced Putative Kinase
chemical_list: D000255:Adenosine Triphosphate; D002118:Calcium; D011494:Protein Kinases; D017382:Reactive Oxygen Species; D000099202:PTEN-Induced Putative Kinase